Python 3.9.0 (Global) failed to start up (exit code 1) - It was working but now consistently fails.

Positron
1

Positron on a 2024 14" M4 MacBook Pro
Running Mac Sequoia 15.6 with 24GB

Console reports the following:
Python 3.9.0 (Global) failed to start up (exit code 1)

The process exited abnormally (exit status: 1)
Traceback (most recent call last):
File "/Applications/Positron.app/Contents/Resources/app/extensions/positron-python/python_files/posit/positron_language_server.py", line 10, in
from positron.positron_ipkernel import (
File "/Applications/Positron.app/Contents/Resources/app/extensions/positron-python/python_files/posit/positron/positron_ipkernel.py", line 18, in
import psutil
File "/Applications/Positron.app/Contents/Resources/app/extensions/positron-python/python_files/lib/ipykernel/arm64/cp3/psutil/init.py", line 116, in
from . import _psosx as _psplatform
File "/Applications/Positron.app/Contents/Resources/app/extensions/positron-python/python_files/lib/ipykernel/arm64/cp3/psutil/_psosx.py", line 13, in
from . import _psposix
File "/Applications/Positron.app/Contents/Resources/app/extensions/positron-python/python_files/lib/ipykernel/arm64/cp3/psutil/_psposix.py", line 21, in
from . import _psutil_osx
ImportError: dlopen(/Applications/Positron.app/Contents/Resources/app/extensions/positron-python/python_files/lib/ipykernel/arm64/cp3/psutil/_psutil_osx.abi3.so, 0x0002): tried: '/Applications/Positron.app/Contents/Resources/app/extensions/positron-python/python_files/lib/ipykernel/arm64/cp3/psutil/_psutil_osx.abi3.so' (mach-o file, but is an incompatible architecture (have 'arm64', need 'x86_64')), '/System/Volumes/Preboot/Cryptexes/OS/Applications/Positron.app/Contents/Resources/app/extensions/positron-python/python_files/lib/ipykernel/arm64/cp3/psutil/_psutil_osx.abi3.so' (no such file), '/Applications/Positron.app/Contents/Resources/app/extensions/positron-python/python_files/lib/ipykernel/arm64/cp3/psutil/_psutil_osx.abi3.so' (mach-o file, but is an incompatible architecture (have 'arm64', need 'x86_64'))

Log file shows the following:
2025-08-07 11:40:27.367 [info] ** Begin kernel log for session Python 3.9.0 (Global) (python-77a5e3bc) at 8/7/2025, 11:40:27 AM **
Streaming kernel log file: /var/folders/nd/2zpsrqlj7tbghpf91g560r_m0000gn/T/kernel-YLSrFN/kernel.log

Other Observations
Python 3.9 executes without error when launched from the terminal

python3.9
John@mac ~ % python3.9
Python 3.9.0 (v3.9.0:9cf6752276, Oct 5 2020, 11:29:23)
[Clang 6.0 (clang-600.0.57)] on darwin
Type "help", "copyright", "credits" or "license" for more information.

  1. R kernel 4.5.1 continues to work just fine, no issue here.
  2. Uninstall & reinstalling all Positron Python extensions failed to resolve the issue.
  3. Uninstalling & reinstalling Positron failed to resolve the problem.
    Positron appears to leave vestiges upon deletion.
    Hence Positron did not return to its origional conditions with an operating Python kernel.
  4. No uninstaller found within the Positron package contents for a more complete deletion.
2

Hi there! Thank you so much for reporting this, I'm sorry you're running into these issues! To help debug this:

  • Are you able to say more about the Python you are using, like where it was downloaded from or the environment type? eg, Conda, uv, Pyenv, Miniconda, etc
  • If you go to Settings (gear in bottom left corner) -> search Use Bundled Ipykernel, is that box checked for you?
  • What version of Positron are you using?

To help get you going in the short term, you can uncheck the "Use bundled IPyKernel" setting, and use the Terminal to manually install ipykernel into the desired Python with pip install ipykernel. One other thing to note: it looks like the console is trying to start up with a global, system Python, which can run into issues when you try to use it. I'd recommend using the "Select Interpreter" dropdown to use a different Python if you have one available!

Let me know if this helps, or we can look into other ways to get you unstuck :raising_hands:

3
  1. I used the Python 3.9 installer from Download Python | Python.org
  2. Yes, the "Python Use Bundled ipykernel" checkbox is checked.
  3. My Positron version is:
    Positron Version: 2025.08.0 (Universal) build 130
    Code - OSS Version: 1.102.0
    Commit: 76ddce53e85437b013671fe7d91a3a1c54f48341
    Date: 2025-08-01T20:09:11.051Z
    Electron: 35.6.0
    Chromium: 134.0.6998.205
    Node.js: 22.15.1
    V8: 13.4.114.21-electron.0
    OS: Darwin arm64 24.6.0
  4. I have unchecked the "Use bundled iPyKernel" as suggested, and
  5. I used pip3 to install ipykernel
  6. I don't usually use "global, system Python" but in my effort to resolve this issue tried several versions
    such as: Python 3.9.0 (global) and Python 3.9.0 (Venv: Learning)

With your (these) suggested changes and restarting Positron I find that (1) Python 3.9.0 (Venv: Learning) has disappeared from the list of Kernels, and (2) the Python 3.9.0 (Global) kernel now starts and executes without issue.